Just over a metre (three feet) from snout to tail, Inermorostrum xenops was half the size of the common bottlenose dolphin. "Short snouts typically occur in Odontoceti that are adept at suction feeding -- the smaller the oral opening, the greater the suction," he said in a statement. The dwarf dolphins were not the only "toothed whales" undergoing rapid evolution at that time. During the Oligocene age, 25 to 35 million years ago, other echolocating cetaceans developed long, toothy snouts specialised in catching fish. Some dolphins, such as the modern bottlenose, settled on a happy medium between the extremes, "the optimum length as it permits both fish catching and suction feeding," Boessenecker added.

Source: The Nation Bangkok August 22, 2017 23:03 UTC